• Category
  • Length Range
    32-56 µm
  • Width Range
    6.5-9.0 µm
  • Striae in 10 µm
  • Synonyms
    Gomphonema montanum var. pumila (Grunow in Van Heurck) Temp. and H.Perag. 1908
  • Reported As
    Gomphonema acuminatum var. pusillum (Thomas et al. 2009 Pl. 1 Figs 5-8)



Valves are linear-acute and biconstricted, with the broadest portion of the valve near the headpole. The center of the valve is slightly tumid and the headpole is acute. The axial area is straight with the central area barely differentiated and transverse. The raphe is lateral and undulate. Striae are punctate. Striae are radiate about the middle portion of the valve, becoming parallel to radiate towards the headpole and parallel to strongly radiate at the footpole. Striae at the central area are slightly more separate from the others. On one side of the central area a stria is reduced in length, on the other side the central stria terminates at the rounded stigma.


Original Description

  • Basionym
    Gomphonema acuminatum var. pusilla
  • Author
    Grunow in Van Heurck 1880


Sep 19, 2016 - Change in rank

This page was originally posted as Gomphonema acuminatum var. pusilla Grunow in Van Heurck. Based on the change in rank from variety to species by Kulikovskiy and Kociolek (Kulikovskiy et al. 2015), the taxon page was updated. Note that the transfer incorrectly states the basionym as G. acuminatum var. pusillium, rather than G. acuminatum var. pusilla. - S. Spaulding

Cite This Page

Kociolek, P. (2011). Gomphonema pusillum. In Diatoms of North America. Retrieved May 30, 2024, from https://diatoms.org/species/gomphonema_pusillum


The 15 response plots show an environmental variable (x axis) against the relative abundance (y axis) of Gomphonema pusillum from all the stream reaches where it was present. Note that the relative abundance scale is the same on each plot. Explanation of each environmental variable and units are as follows:

ELEVATION = stream reach elevation (meters)
STRAHLER = distribution plot of the Strahler Stream Order
SLOPE = stream reach gradient (degrees)
W1_HALL = an index that is a measure of streamside (riparian) human activity that ranges from 0 - 10, with a value of 0 indicating of minimal disturbance to a value of 10 indicating severe disturbance.
PHSTVL = pH measured in a sealed syringe sample (pH units)
log_COND = log concentration of specific conductivity (µS/cm)
log_PTL = log concentration of total phosphorus (µg/L)
log_NO3 = log concentration of nitrate (µeq/L)
log_DOC = log concentration of dissolved organic carbon (mg/L)
log_SIO2 = log concentration of silicon (mg/L)
log_NA = log concentration of sodium (µeq/L)
log_HCO3 = log concentration of the bicarbonate ion (µeq/L)
EMBED = percent of the stream substrate that is embedded by sand and fine sediment
log_TURBIDITY = log of turbidity, a measure of cloudiness of water, in nephelometric turbidity units (NTU).
DISTOT = an index of total human disturbance in the watershed that ranges from 1 - 100, with a value of 0 indicating of minimal disturbance to a value of 100 indicating severe disturbance.